Get the featured image by page ID in WordPress

gistfile1.txt

<?php
//page id
  $page_id = "5"; //example

  if (has_post_thumbnail($page_id) ):
    $image = wp_get_attachment_image_src( get_post_thumbnail_id($page_id), 'single-post-thumbnail' );
   endif;
   
   $image_URI = $image[0];
  
?>
You can also use an array to fetch images from multiple pages.
<?php
//page id
  $page_id = array('5', '10', '17'); //example stores multiple page ID in an array

//render image for each page using foreach conditional loop
foreach($page_id as $id){

  if (has_post_thumbnail($id) ):
    $image = wp_get_attachment_image_src( get_post_thumbnail_id($id), 'single-post-thumbnail' );
   endif;
   
   echo "<img src='".$image[0]."'>";

} 
?>